On Tuesday, July 21, 2015 at 9:07:11 PM UTC-4, dpb wrote:
On 07/21/2015 7:29 PM, wrote:
Manufacturer FINALLY got back to me this evening!
It's 11.2 amps at 110V, so only 6 amps at 220V.

That makes a lot more sense on the motor size. Now the question is, is
it a dual-voltage motor?

That said, I used the above website to calculate the voltage drop at 8volts over 300LF. This is 3.5%, which I beleive is quite acceptable.

I think I'm good, yes?

That's too much for a motor circuit if that's what you computed for the
running voltage; you'll be way under that during starting.

(all technical opinions greatly appreciated, especially dissenting ones)

The table again shows you can go 340-ft 240V for 1/2 hp w/ #10 but only
220-ft w/ #12 (which, w/o looking is what I'd guess the above voltage
drop would be for).

I'm saying you need #10.

--

Yes, it's definitely a dual voltage motor.
Yes, you are correct in that my voltage drop calculation is incorrect (used the wrong current) and I just redid and found only a 4.5volt drop (2% drop).
Yes, I plan on going with #10.

Thank you, evereyone, VERY much for the advice, all of which was well-referenced and thought out.